Process of separation.



H. A. WENTWORTH.

PROCESS OF SEPARATION.

APPLICATION FILED AUG. 18, 1908.

970,002, Patented Sept. 13, 1910.

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dred phenomena may be availed of to UNITED STATES PATENT OFFICE.

HENRY AZOR WENTWORTH, OF LYNN, MASSACHUSETTS, .ASSIGNOR TO HUFF ELECTRO- STATIC SEPARATOR COMPANY, 013 BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

PROCESS OF SEPARATION.

Specification of Letters Patent.

PatentedSept. 13, 1910.

To all whom it may concern:

Be it known that I, HENRY A201: WENT- WORTH, a citizen of the United States, and resident of Lynn, in the county of Essex and State of Massachusetts, have invented new and useful Improvements in Processes of Separation, of which the following is a specification.

My invention relates to the concentration or separation of the ingredients of mixed solid material, comminuted as by granulation such as in the crushedrock, or earth which bears valuable minerals or ores and from which it is necessary or desirable to separate the commercially valuable materials from the inferior ingredients, all of which may possess commercial value when segregated, but which, when mingled, interfere mutually with processes, such as smelting, which for their bestresults require comparatively pure materials to work upon.

My new process involves, first: the treatment of a mixed heterogeneous mass of particles by, or its subjection to; a reagent which enters into chemical combination with the substance of the particles themselves, or with that of some particles as distinguished from others, to an extent sufficient to form upon the surfaces of the affected particles, compounds which differ in constitution both from the reagent'and the original particles, and which exhibit in contact with a liquid a degree of avidity for the liquid different from that ossessed by such solid particles when una ected or not prepared by, such reactive treatment. By causing a chemical change to take place in one or more of the ingredients of which the particles of the mixture are composed, so that some particles are, to a substantial extent changed superficially at least, differential behavior of the changed and unchanged particles in respect to susceptibility to contact with a liquid is of this ifferential uality, theeffects of liquid adhesion, sur ace-tension, and kin- (produced, or enhanced. By means 7 treatment, according to the nature of the mixture of solids and also that of the reagent, may specifically present either of the followin characteristic changes: The superficially deposited compound upon particles constituting one ingredient may render those particles strikingly less susci ptible to wetting, by a selected liquid, than is the case with such particles ordinarily, while other particles may be affected by the reagent insensibly or not at all; or,the superficially deposited compound may render those particles to which it attaches far more susceptible to wetting by a selected liquid than they are ordinarily, while other particles are affected by the reagent insensibly or not at all; or,ot' two ingredient sets of particles, one may receive a superficial formation deposit of a compound which is susceptible to wetting than the particles were originally, while another may receive a superficial deposit of a compound which is more susceptible to wetting than .the untreated particles of this class; and

thus the two ingredient sets of particles will become widely divergent in character, in respect to their behavior toward filmtension (so called) as at the surface of a liquid. An example of separation which depends upon differential capacities for becoming wetted by a liquid, differential avidities for the liquid, so to speak, is furnished when the particles of the mixture, after having been subjected to the action of a chemical reagent which acts, as above set forth, differentially upon the several ingredients, are transferred to a body of liquid which, by reason of the previously produced or enhanced differential properties of particles in respect to wetting or surface-tension, will make intimate contact with the surfaces of some particles, and will refuse to make such contact with others; the

result being, that the wetted particles are engulfed and sink, while the unwetted particles are sustained by sl1rface-tension,'and float. But the specific mode by which difduce a separation of one class of particles ferential avidity for a liquid (as the term is from others. The effect of such reactive defined hereinabove) may be availed of for separation does not. necessarily involve the.

deposition of material uponthe surface of a body of liquid. If the materials are first completely immersed'in a liquid, are therein chemically treated to produce difierential avidity .for the liquid and then subjected to. the formation of gas- 'ubbles; the bubbles will insinuate themselves between the surfaces of the non-wetable particles. and the surpound'ing liquid, and buoy them up to the sur ace.

Particularly my new process generally outlined above is applicable to the case of sulfids, and to mixtures which contain several sulfids ns for instance zinc sulfid and iron sulfid? The reagent employed in the case of such sulfid mixtures is a halogen, preferably chlorin. While fluorin or iodin may be technically effectual, their employment presents practical obstacles;.'bromin, while more available than these two, is less easily obtained than chlorin, the most common representative of the halogen class.

Whatever may be the specific exemplification of the preparatory treatment above generally characterized, it is to be-followed by the presentation of the mass after preparation to conditions favorable to theoperation of film or surface tension, as at the surface of a liquid (according to the specific illustration hereinbelow set forth), sothat the film or surface tension thereof sustains some particles, while others are wetted and engulfed. V

I am awarethat flotation processes of separatlon have been employed heretofore, that in some instances the natural behavior of two ingredients of a mixture in respect to a surface of liquid has accomplished separation, that in other instances the behavior of a class of particles with respect to the surface of a liquid has been-altered by, coating the particles with oil or like water-shedding substance, andthat'in other instancesreactions have been set up which cause bubbles of gas to form upon and cling to, particles I immersed in a liquid, and to buoy them up.

My process herein. described, unlike those with which I'am acquainted or of which 1 have been informed, is characterized by a reaction between the substance of particles in ingredients of a mixture, the subsequent apdient from another,

view,

surface of abafile plate 'perhaps copper plication of liquid surface tension agencies,

for the purpose of separationof one ingrematerialrespect from well known flotation processes of separation.

In the drawings hereto annexed there is illustrated an'apparatus suited to the performance of my new separative process; in

these Figure 1 represents a longitudinal eleneed not differ in any vation, partly section, of the apparatus;

shows the same apparatus in plan and Fig. 3 shows the apparatus in front elevation partly broken away and partly in section.

In these figures the major part of the-supporting frame Work is not shown.

An endless belt B,',which may be a canvas belt, is carried over a driving rollerA, guide rollers, E, E, and G, under a sprinkling pipe G and through a box D. From the guide r ler E the belt B dips beneath the surface T of water in the tank T, and returns around the roller F lying'beneaththe surface of the water, supported upon a frame f; and thence to the lower guide roller G to the roller A; a hopper H serves to deliver the ore or other mixture, M (in properly'comminuted condition) to the surface of the belt B which travels in the direction indicated by the arrow at the roller A. Water is conducted into the tank T in a gentle stream from the pipe W; this stream impinges against the I which is mounted Fig. 2

upon the side of the tank on legs vided the projecting lip. T below this lip there is mounted a belt N passing over and driven by'a roller L. Within 'the tank and extending at right angles to the belt B, the belt K travels under the guide roller K over the external guide rollers K and K passing beneath the through which the belt B,

to the tank T.

If now for example, a mixture such as 1s found in a number of so-called blackjack' zinc ores, be delivered to the belt B from the hopper H, this mixture containing, say, zinciron sulfid with a proportion of iron sulfid dissociated from-the zinc sulfid, lead sulfid, sulfid and a silicious gangue, 1t will be spread upon the belt .13 by the movement thereof and carried under the sprinkling pipe C which delivers through suitable apertures a stream of water su ciently copious to moisten the mineral mixture thoroughly and yet not sufficiently copious to. wash the same off .the belt. Thence the material passes with the belt into the box D. Meanwhile a stream of a halogen, preferably chlorin,

the box through the pipes D so that the At the I side of the tank opposite the pipe W is prois introduced into.

tank T in its return move- -ment. Pipes D lead into the upper portion .of the box D passes in its movement from the hopper H moist material is sufiiciently chlorinated, during its passage through the box. The material thus treated with a halogen passes with the belt from the box I) down to the to effect this useful preliminary moistening of the particles. The chlorin undoubtedly goes into a concentrated solution in the water-films which cling to the particles, and is thus brought into intimate reactive contact with the substance of the particles themselves. Examination of zinc sulfid particles thus treated discloses coats, films, or blotches, of an oily appearing compound, which is probably a chlorid of sulfur, and these coats or blotches, constitutionally different from either the zinc sulfid or the chlorin, because a resultant compound of both. renders the particles which bear them decidedly averse to becoming wetted by water; far more so than the zinc sulfid particle itself before treatment. Particles of zinc sulfid of such size that they would, in their natural condition although dry overcome the surface tension of a body of water and sink therein, will after a halogen treatment, be sustained upon the surface of the liquid. \Vith iron suliid, on the contrary, the effect of the halogen upon the surface of the solid material appears and is believed to be the formation of a halogen compound, probably with the iron itself, which is very readily'soluble in water, or at all events, manifests decided avidity for water, so that iron sulfid upon coming in contact with the water is more readily wet-- ted, seems to attract rather than to repel the water, and so that the surface tension of the liquid is overcome even more quickly than will be the case with iron sulfid in its ordinary condition. This may be demonstrated by taking finely comminuted iron sulfid,

whereof the dimensions of the particles are so small that ordinarily they would float freely upon the surface of the water. If these be superficially treated with the halogen, especially inassociation with moisture and then placed upon the surface of the water, they are promptly engulfed and settle in the liquid.

At the point where the belt B enters the water in the tank T, the zinc sulfid will be floated off upon the surface of the water, while the other components of the material are submerged and fall from the belt B as it turns on the roller F, and settle upon the belt K. The fiow of liquid in the tank out over the lip T carries with it the scum of finely comminuted floating zinc sulfid together with zinc sulfid particlcs'of considerable size, all of which are floated by the surface tension of the water, and escape over the lip T upon the belt N from which they may be collected. The other components of the'm'aterial are carried by the movement of the belt K out of the tank and may be deposited in any suitable receptacle or conveyed away by any suitable means. If the mixture under treatment is, for instance, a zinc sulfid mechanically combined with particles of tluorspar such as is found in some of the Kentucky zinc ores, the fluorspar does not appear to behave otherwise that it would in its natural condition; if this mixture is subjected to the above described process in an apparatus similar to that illustrated in the drawings, the zinc sulfid particles become more resistant to water absorptionand are sustained by the surface tension of the water or other liquids, whereas, the fluorspar be comes moistened, if not already moistened, and sinks at a rate for which its'mass is responsible.

As a furthzr illustration of the value of my above described process, if one takes a comminuted ore containing chalcopyrite and iron pyrite, the behavior of the ingredients is as follows: In the preliminary process of comminution, the chalcopyrite breaks up into thin scales which, without any further treatment, float easily upon the water; this propensity for floating has heretofore proved troublesome in the use ofwvatcr tables in which it is ditticult to prevent the escape and loss of fine particles of chalcopyrite. Moreover, the fine particles of iron pyrite if placed in water without any previous treatment float substantially as readily and freely as the chalcopyrite flakes, and separation by this means is thereby dcfeated. If we now subject such a mixture to the chemical influence of a halogen in the manner above described, the halogen reacts promptly upon the iron pyrite and much more slowly or not at. all upon the chalcopyrite, thus leaving the chalcopyrite particles practically in their natural condition, but so converting or affecting the surfaces of the iron pyrite particles that they possess an unusual avidity for water. Then, when the mixture is introduced into a tank containing water the chalcopyrite particles are separated from the iron pyrite because of the natural tendency of the former to float, (that is to say, to be sustained by the surface tension of the water) and the artificially prmluccd tendency of the latter to become superficially coated or wetted with the water. A similar behavior of the particles for the same reason, will be observed if the mixture is introduced directly, and

' viating the time during which the mixture,

&

without preliminary treatment, into water containing a halogen in' solution;'then the halo entreatment and the differential flotatioi and immersion effects are substantially simultaneous. In treating ores of the last named character, it is advisable to limit the' halogen treatment, either by abbreis in the presence of the halo en or by attenuating the halogen as by so ution. so that the chalcopyrite does not have suflicient opportunity to become affected, which" might be the case if the treatment were vigorous or protracted.

When an apparatus such as above described is employed, the body of water upon-the belt conveyer isin effect a continuationof that more apparent body of water in the tank. Whenever the preparatory reaction is practically instantaneous, the material need not be supported as by a belt after the reaction begins, but may be carried to the liquid surface, prepared for flotation at the first touch of the reagentsuspended in solution in the liquid, and be floated (or immersed) at apparently the same instant. In other words, when an appreciable time is required to complete the preparatory superficial reaction upon the particles.' (.or some of them) some .mode of support is desirable or necessary to sustain as well as convey the material to the surface of the liquid where the preliminary treatment manifests its functions in the fact of separation by flotation of some and immerliquid which is carried by the conveyor will suflice to promote the preliminary reaction, whichmi ht indeed, be effected under the surface 0 a more copious body of liquid whence the particles might then be mechanically'emersed to be again presented to the surface of the liquid, where separation takes place. Preparation of ingredient particles, as herein described renders the mass susceptible to any flotation separation process.

wherein film tension plays a functional part, as in those processes where gas bubbles are made to form in a liquid and insinuate themselves so to speak between the liquid and those particles which are superficially so constituted as to resist wetting, and thereaftepbupy, up the ..1&rti cles to which 55" hat I claim, and desire to secure by Letters Patent is:

1. The process of original substance of the particles in respect a superfici I separating ingredients of comminutedmaterial, which consists in,

separating the differentiated particles by-v film-tension of said liquid.

2. Theprocess of separating the ingre A die-nts of comminuted material containing a Ir :tallic sulfid, which consists in treating the materialwith a halogen, thereby producing upon the sulfidpapticles aifectedby the halogen, superficial coatings of a compound difi'ering from theloriginal sulfid particles in respect to film-tension of a quid, and thereupon separating thediiferentiated particles, by film-tension of said liquid. 3. The process of separating ingredients of comminuted'material containing a metallic sulfid, which consists in treating the material with a halogen, therebyproducing upon the sulfid a compound possessing a superficial aversion for aliquid, transferring the material to the surface of a body of said liquid, and separately collecting the particles of the sulfid sustained by the sur-' face tension of the liquid, and those engulfed thereby.

4. The process of separating ingredients of comminuted material containing a metallic sulfid, which consists in treating the material with a halogen, forming a halid of sulfur superficially upon particles of metallic sulfid, thereby altering the said particles in respect to film-tension of a liquid, and thereupon utilizing the said altered property of these particles to effect flotation separation by said liquid.

5'. The process of separating zinc sulfid from materials associated therewith in a comminuted mixture," which consists in chemically producing upon the zinc sulfid a compound averse to contact with water, transferrin the material to the surface of a body 0 water, and separately collecting the particles sustained by the surface tension of the water, and those engulfed thereby.

6. The process ofseparating zinc sulfid from --materials associated therewith in a comminuted' mixture, which consists in treating the mixture with ahalogen, and

producing upon thezinc sulfid a compound possessing a marked superficial aversion for water, transferring the material to the surface of a body of water, and separately collectingthe particles of sulfid sustained by the surface tension of the water, and those particles engulfed thereby.

l 7. The'process of separating comminuted I material which consists in associating the pound which enhances difierence in the material with a liquid, and treating the material with a halogen, producing a com-' avidity of its several ingredients for the liquid, and subjecting the mixture to flotation separation.

8. The process of separating zinc sulfid subjecting the mixture to flotation-separafrom materials associated therewith in 21 tion by a body of Water. 10 comminuted mixture, Which consists in in- Signed b me at Boston, Massachusetts troducing the mixture into contact with this fifteenth day of August 1908.

5 water and then treating the mixture with a HENRY AZOR WENTWORTH.

halogen, and producing upon the zinc sul- Witnesses: fid a compound possessing marked super- ROBERT OUSHMAN,

ficial aversion for water, and thereafter JOSEPHINE H. RYAN. 

